Caesar Cipher

Introduction

The Caesar Cipher is a simple and widely known encryption technique that uses substitution to shift letters in the alphabet by a fixed number of positions. It is a type of monoalphabetic cipher and one of the earliest known encryption methods.

Features

• Encrypts plaintext using a shift key
• Decrypts ciphertext back to plaintext
• Supports uppercase and lowercase letters
• Can handle custom shift values

How It Works

Each letter in the plaintext is shifted forward in the alphabet by a fixed number of positions determined by the shift key. If the shift reaches the end of the alphabet, it wraps around to the beginning.

For example, with a shift key of 3:

• Plaintext: HELLO
• Ciphertext: KHOOR

Installation

To use this implementation, clone the repository and navigate to the project directory:

git clone https://github.com/your-repository/caesar-cipher.git
cd caesar-cipher

Usage

Encryption

from caesar_cipher import encrypt

plaintext = "HELLO"
shift = 3
ciphertext = encrypt(plaintext, shift)
print("Encrypted Text:", ciphertext)

Decryption

from caesar_cipher import decrypt

ciphertext = "KHOOR"
shift = 3
plaintext = decrypt(ciphertext, shift)
print("Decrypted Text:", plaintext)

Example

Input: HELLO, Shift: 3
Output: KHOOR

Limitations

• Only supports alphabetic characters (A-Z, a-z)
• Does not encrypt numbers or special characters

License

This project is open-source and available under the MIT License.